weidong3630 commented on a change in pull request #1606: [CALCITE-3466] Do not
drop the "group by" clause of subquery in a select statement with "group by"
clause in JDBC adapter.
URL: https://github.com/apache/calcite/pull/1606#discussion_r365819703
##########
File path:
core/src/main/java/org/apache/calcite/rel/rel2sql/SqlImplementor.java
##########
@@ -1224,10 +1224,18 @@ public Builder builder(RelNode rel, Clause... clauses)
{
needNew = true;
}
}
- if (rel instanceof Aggregate
- && !dialect.supportsNestedAggregations()
- && hasNestedAggregations((Aggregate) rel)) {
- needNew = true;
+
+ if (rel instanceof Aggregate) {
+ Aggregate e = (Aggregate) rel;
+ final boolean nestedAgg = hasNestedAggregations(e);
+ if (withGroupBy() && (!e.getGroupSet().toList().isEmpty()
+ || !nestedAgg || !dialect.supportsNestedAggregations())) {
Review comment:
> How about this code:
>
> ```java
> if (rel instanceof Aggregate) {
> final Aggregate agg = (Aggregate) rel;
> final boolean hasNestedAgg = hasNestedAggregations(agg);
> if (!dialect.supportsNestedAggregations()
> && hasNestedAgg) {
> needNew = true;
> } else {
> if (this.clauses.contains(Clause.GROUP_BY)) {
> // Avoids to lose the distinct attribute of inner agg.
> if (!hasNestedAgg || Aggregate.isNotGrandTotal(agg)) {
> needNew = true;
> }
> }
> }
> }
> ```
Yeah, it's simpler to my code and it's equivalent to my code.But I think
that the logic is still a bit confusing.
How about this:
```java
if (rel instanceof Aggregate) {
final Aggregate agg = (Aggregate) rel;
final boolean hasNestedAgg = hasNestedAggregations(agg);
if (hasNestedAgg) {
if (!dialect.supportsNestedAggregations()) {
needNew = true;
}
} else {
if (this.clauses.contains(Clause.GROUP_BY) &&
Aggregate.isNotGrandTotal(agg)) {
// Avoids to lose the distinct attribute of inner agg.
needNew = true;
}
}
}
```
Is the logic more clear?
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